<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
            list-style: none;
            text-decoration: none;
        }
        .ulist{
            width: 50%;
            height: 30px;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }
        .ulist li.active{
            color: red;
        }
        .olist li{
            display: none;
        }
        .olist li.active{
            display: block;
        }
    </style>
</head>
<body>
    <ul class="ulist">
        <!-- <li></li>
        <li></li>
        <li></li>
        <li></li> -->
    </ul>
    <ol class="olist">
        <!-- <li></li>
        <li></li>
        <li></li>
        <li></li> -->
    </ol>
    <script src="./index.js"></script>
</body>
</html>